The invention relates to internal combustion engines run on kerosene fuel. The invention particularly arose during development efforts to provide a two cycle internal combustion engine which can be started solely with kerosene, without the assist of gasoline.
Kerosene and similar fuels have higher distillation temperatures than gasoline. In the prior art, a kerosene engine is started with gasoline. After starting, the gasoline is mixed in variable quantities with kerosene to facilitate smooth operation until the engine reaches sufficient operating temperature that the kerosene alone will vaporize and can be ignited by the spark plug. In a diesel engine, the fuel-air mixture temperature is raised so high by the extraordinarily high compression ratio that it is ignited without a spark plug. In a kerosene engine, the fuel-air mixture temperature required for spark plug ignition is substantially less than that for diesel ignition.
In many areas of the world kerosene fuel is preferred because it is cheaper, or in many cases is the only fuel available. It is therefore desirable to provide an engine which can be operated solely on kerosene, totally excluding the use of gasoline. Diesel ignition is not desirable because of the significantly increased cost of the components necessary to withstand the higher compression ratios. A spark ignition type engine is less costly, due to its lower compression ratios and lower stress on components.
The primary problem in totally excluding the use of gasoline in a spark ignition kerosene engine is the problem of starting the engine.